Effects of Nigella sativa on endothelial dysfunction in diabetes mellitus: A review

Ethnopharmacological relevance: Endothelial dysfunction is involved in lesion generation by the promotion of both early and late mechanism(s) of atherosclerosis such as adhesion molecules up-regulation, increased chemokine secretion and leukocyte adherence, increased cell permeability, enhanced low-density lipoprotein oxidation, cytokine elaboration, platelet activation and vascular smooth muscle cell migration, and proliferation. Nigella sativa is from the Ranunculaceae family which is used in some countries for various medicinal purposes. Nigella sativa seed has been widely used in traditional medicine for the treatment of diabetes. Aim of the review: This review article summarized the therapeutic effects of Nigella sativa on endothelial dysfunction. Methods: Databases such as PubMed, Web of Science, Google Scholar, Scopus, and Iran Medex were considered. The search terms were Nigella sativa or endothelium and Diabetes,endothelial dysfunction, Thymoquinone and anti-inflammatory effect. Results: The current review shows that Nigella sativa and Thymoquinone have a protective effect on endothelial dysfunction induced by diabetes. This is done by several mechanisms such as reduction of inflammatory and apoptotic markers, improving hyperglycemia, hyperlipidemia and antioxidant function, inhibiting platelet aggregation, and regulating eNOS, VCAM-1 and LOX-1 genes expression that involve in the endothelial dysfunction. Thymoquinone also reduces expression and secretion of some cytokines such as MCP-1, interleukin-1 beta, TNF-alpha, NF-kappa B, and Cox-2 that result in anti-inflammation effect. Conclusion: Thymoquinone, the main phenolic terpene found in Nigella sativa, has several important properties such as antidiabetic, anti-inflammatory, and antioxidant activity. Therefore, Nigella sativa can improve endothelial dysfunction.